KWI Series Water Lubricated Oil Free Single Screw Air Compressor | ISO Class 0
The KWI Series 100% Oil Free Water Lubricated Single Screw Air Compressor uses pure water for lubrication, sealing and cooling, delivering ISO Class 0 oil-free compressed air. Available in air-cooled (15–500kW) and water-cooled (37–500kW) versions with VFD inverter, it operates at low ~40℃ discharge temperature, cutting energy use and eliminating oil contamination risk for food, pharma & electronics production.
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Functional Configuration
- VFD Variable Frequency Drive
- High efficiency inverter for fluctuating air demand
- Single Screw Rotor Design
- Balanced low-load bearing structure
- Pure Water Lubrication System
- Water acts for sealing, lubricating & cooling
- Air/Water Cooling Options
- Air cooling 15–500kW, Water cooling 37–500kW
- Super Precision Machined Rotor
- High stability & long service life
- Low-Temp Near-Isothermal Compression
- Discharge air ~40℃, anti heat ignition
Performance Parameters
- Working Pressure
- 7–12.5 bar(g) (102–181 psi)
- Air Delivery
- 1.1–77 m³/min (39–2719 cfm)
- Power Rate
- 7.5–500 kW (10–671 hp)
- Discharge Air Temperature
- Approx. 40℃
- Cooling Types
- Air cooling / Water cooling
Why KWI Series Water Lubricated Single Screw Compressor
Common Air Compression Challenges For Oil-Free Production
- Oil contamination risk ruining pharma, food and electronic products
- High power consumption of traditional oil-free dry screw compressors
- High operating temperature leading to safety hazards
- Expensive oil filter replacement & waste oil disposal costs
- Unbalanced rotor design causing high vibration and bearing wear
How KWI Series Water Lubricated Compressor Solve These Issues
- Pure water lubrication delivers 100% oil-free compressed air
- VFD single screw design optimizes energy use to lower plant electricity bills
- Low ~40℃ discharge temperature eliminates high-temperature ignition risks
- No lubricating oil required, removes oil filter and waste oil management cost
- Balanced single screw rotor reduces bearing load, vibration & noise
Recommended Applications
The undisputed leader of prevent global warming, Energy conservation, and environment protection
The power consumption of air compressor is occupied about 5% among a regional total power consumption. In Particular, due to the power consumption of the compressor takes up 20% ~ 30% of the total power consumption in a plant, cuts down the power consumption of the compressor is the most effective energy saving way.
High-efficiency energy-saving single screw compressor is contributing to prevent of global warming by reducing CO2. In addition, due to using no oil, not only the best way to resolve environment and energy conservation but also ISO14000 measures in water pollution and waste management and HACCP hygiene operations. Moreover, it is very safety from heat ignition due to relatively low compression temperature at about 40℃.
Single-Screw —- Ideal compression mechanism
A simple construction and water-seal effect deliver ideal operating efficiency.
The “Single-Screw” pump’s construction use a single screw rotor and two gate rotors, one placed on either side of the screw rotor.
This is simple construction transmits pressure to the rotating axle with good balance, and prevents excessive load on the bearings this is one of the reasons for the “Single-Screw” pump’s high efficiency. The water used as a lubricating medium also seals gaps inside the compression chamber.
Compressed air is thus kept from leaking, enabling the “Single-Screw” pump to generate sufficient discharge even at low rotating speeds. This reduces both noise and vibration. The cooling effect of the water lubricant also prevent heating from the compression process (the discharge air temperature is about 40℃.), making the compression process more efficient and eliminating the need for a cooling apparatus.
This improves both safety and durability significantly. The fusion of our unique compression mechanism and new water – lubricant technology is helping greatly to improve energy in a wide range of fields.
The center of the rotor has characteristics of SINGLE-SCREW consumption structure that shows high efficiency and stability by utilizing super precision technology of Mitsui Seiki that is also a maker of machine tools.
Frequently Asked Questions
Unlike traditional compressors that use oil for sealing and cooling, the KWI series uses pure water as the lubricating medium. Since there is no oil present in the entire compression system, there is zero risk of oil contamination, ensuring your air meets the strict ISO 8573-1 Class 0 standard.
Not at all. We use high-grade stainless steel for the screw rotors, casings, and piping systems. This specialized material design prevents corrosion and ensures the long-term durability of the air end while maintaining the purity of the compressed air.
Water has a much higher heat absorption capacity than oil. This allows for near-isothermal compression, which is highly efficient. Combined with our VSD (Variable Speed Drive) technology, the KWI series can reduce energy consumption by up to 35% compared to standard fixed-speed compressors.
Actually, it’s simpler and more cost-effective. You don't need to purchase expensive oil filters or deal with waste oil disposal. The primary maintenance involves changing the water filter and air filter. The system even features an automatic water exchange and filtration system to keep the lubrication water clean.
Dry oil-free compressors are often much more expensive and run at higher temperatures. The KWI series provides the same "Class 0" air quality but at a lower initial investment and lower operating temperatures, which extends the lifespan of the seals and bearings.
Yes, the KWI series is designed for heavy-duty industrial applications. The water-lubricated system provides superior cooling performance, allowing the machine to maintain a stable temperature even during continuous full-load operation in demanding environments like pharmaceutical or textile plants.
The compressor is equipped with a built-in high-precision water filtration and reverse osmosis system (optional based on model). This ensures that the lubricating water remains within the required purity levels, protecting the air end from scaling or mineral buildup.
Technical Specifications of KWI Series Air Compressors for Water Well Drilling
| Model | Working Pressure-psig | Working Pressure-bar | Air Delivery-cfm | Air Delivery-m3/min | Motor Power-kw/hp | Type of Cooling | Dimension(mm)-L | Dimension(mm)-W | Dimension(mm)-H | Weight-kg | Output pipe Diameter |
|---|---|---|---|---|---|---|---|---|---|---|---|
| KWI-7.5A | 100 / 116 / 145 / 181 | 7 / 8 / 10 / 12.5 | 38.8 / 35.3 / 30.0 / 24.7 | 1.1 / 1 / 0.85 / 0.7 | 7.5/10 | Air / Water Cooling | 1300 | 800 | 1300 | 500 | 3/4" |
| KWI-11A | 100 / 116 / 145 / 181 | 7 / 8 / 10 / 12.5 | 63.6 / 58.3 / 53.0 / 45.9 | 1.8 / 1.65 / 1.5 / 1.3 | 11/15 | Air / Water Cooling | 1300 | 800 | 1300 | 540 | 1" |
| KWI-15A | 100 / 116 / 145 / 181 | 7 / 8 / 10 / 12.5 | 84.7 / 77.7 / 74.2 / 63.6 | 2.4 / 2.2 / 2.1 / 1.8 | 15/20 | Air / Water Cooling | 1620 | 1004 | 1410 | 650 | 1" |
| KWI-18.5A | 100 / 116 / 145 / 181 | 7 / 8 / 10 / 12.5 | 109.5 / 102.4 / 95.3 / 81.2 | 3.1 / 2.9 / 2.7 / 2.3 | 18.5/25 | Air / Water Cooling | 1600 | 910 | 1350 | 840 | 1" |
| KWI-22A | 100 / 116 / 145 / 181 | 7 / 8 / 10 / 12.5 | 134.2 / 127.1 / 113.0 / 88.3 | 3.8 / 3.6 / 3.2 / 2.5 | 22/30 | Air / Water Cooling | 1450 | 1000 | 1560 | 870 | 1" |
| KWI-30A | 100 / 116 / 145 / 181 | 7 / 8 / 10 / 12.5 | 187.1 / 176.6 / 151.8 / 127.1 | 5.3 / 5 / 4.3 / 3.6 | 30/40 | Air / Water Cooling | 1950 | 1050 | 1432 | 980 | 1 1/4" |
| KWI-37A | 100 / 116 / 145 / 181 | 7 / 8 / 10 / 12.5 | 233.0 / 218.9 / 201.3 / 162.4 | 6.6 / 6.2 / 5.7 / 4.6 | 37/50 | Air / Water Cooling | 1700 | 1100 | 1630 | 1000 | 11/4" |
| KWI-45A | 100 / 116 / 145 / 181 | 7 / 8 / 10 / 12.5 | 282.5 / 271.9 / 243.6 / 211.9 | 8 / 7.7 / 6.9 / 6 | 45/60 | Air / Water Cooling | 2150 | 1300 | 1590 | 1060 | 11/2" |
| KWI-55A | 100 / 116 / 145 / 181 | 7 / 8 / 10 / 12.5 | 370.8 / 346.0 / 307.2 / 257.8 | 10.5 / 9.8 / 8.7 / 7.3 | 55/75 | Air / Water Cooling | 2200 | 1400 | 1540 | 1250 | 2" |
| KWI-75A | 100 / 116 / 145 | 7 / 8 / 10 | 480.2 / 459.0 / 409.6 | 13.6 / 13 / 11.6 | 75/100 | Air / Water Cooling | 2400 | 1450 | 1740 | 1480 | 2" |
| KWI-90A | 100 / 116 / 145 | 7 / 8 / 10 | 572.0 / 547.3 / 494.3 | 16.2 / 15.5 / 14 | 90/120 | Air / Water Cooling | 2550 | 1400 | 1605 | 2030 | DN50 |
| KWI-110W | 100 / 116 / 145 | 7 / 8 / 10 | 734.4 / 688.5 / 582.6 | 20.8 / 19.5 / 16.5 | 110/150 | Air / Water Cooling | 2700 | 1550 | 1750 | 2450 | DN65 |
| KWI-132W | 100 / 116 / 145 | 7 / 8 / 10 | 847.7 / 812.1 / 706.2 | 24 / 23 / 20 | 132/175 | Air / Water Cooling | 2600 | 1650 | 1750 | 2850 | DN65 |
| KWI-160W | 100 / 116 / 145 | 7 / 8 / 10 | 981.6 / 935.7 / 829.8 | 27.8 / 26.5 / 23.5 | 160/200 | Air / Water Cooling | 3300 | 2200 | 2000 | 3750 | DN65 |
| KWI-200W | 100 / 116 / 145 | 7 / 8 / 10 | 1218.2 / 1165.2 / 988.7 | 34.5 / 33 / 28 | 200/270 | Air / Water Cooling | 3300 | 2200 | 2200 | 4100 | DN80 |
| KWI-250W | 100 / 116 / 145 | 7 / 8 / 10 | 1518.3 / 1412.4 / 1306.5 | 43 / 40 / 37 | 250/330 | Air / Water Cooling | 3670 | 2070 | 2370 | 4750 | DN125 |
| KWI-280W | 100 / 116 / 145 | 7 / 8 / 10 | 1800.8 / 1765.5 / 1589.0 | 51 / 50 / 45 | 280/375 | Air / Water Cooling | 4000 | 2000 | 2100 | / | DN150 |
| KWI-315W | 100 / 116 / 145 | 7 / 8 / 10 | 1977.4 / 1942.1 / 1730.2 | 56 / 55 / 49 | 315/420 | Air / Water Cooling | 4600 | 2300 | 2400 | / | DN125 |
| KWI-400W | 100 / 116 / 145 | 7 / 8 / 10 | 2259.8 / 2471.7 / 2153.9 | 64 / 70 / 61 | 400/550 | Air / Water Cooling | 4600 | 2300 | 2400 | / | DN150 |
| KWI-450W | 100 / 116 / 145 | 7 / 8 / 10 | 2860.1 / 2789.5 / 2471.7 | 81 / 79 / 70 | 450/600 | Air / Water Cooling | 5500 | 2590 | 2800 | / | DN175 |
| KWI-500W | 100 / 116 / 145 | 7 / 8 / 10 | 3142.6 / 3072.0 / 2718.9 | 89 / 87 / 77 | 500/670 | Air / Water Cooling | 5500 | 2590 | 2800 | / | DN200 |
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Frequently Asked Questions
Unlike traditional compressors that use oil for sealing and cooling, the KWI series uses pure water as the lubricating medium. Since there is no oil present in the entire compression system, there is zero risk of oil contamination, ensuring your air meets the strict ISO 8573-1 Class 0 standard.
Not at all. We use high-grade stainless steel for the screw rotors, casings, and piping systems. This specialized material design prevents corrosion and ensures the long-term durability of the air end while maintaining the purity of the compressed air.
Water has a much higher heat absorption capacity than oil. This allows for near-isothermal compression, which is highly efficient. Combined with our VSD (Variable Speed Drive) technology, the KWI series can reduce energy consumption by up to 35% compared to standard fixed-speed compressors.
Actually, it’s simpler and more cost-effective. You don't need to purchase expensive oil filters or deal with waste oil disposal. The primary maintenance involves changing the water filter and air filter. The system even features an automatic water exchange and filtration system to keep the lubrication water clean.
Dry oil-free compressors are often much more expensive and run at higher temperatures. The KWI series provides the same "Class 0" air quality but at a lower initial investment and lower operating temperatures, which extends the lifespan of the seals and bearings.
Yes, the KWI series is designed for heavy-duty industrial applications. The water-lubricated system provides superior cooling performance, allowing the machine to maintain a stable temperature even during continuous full-load operation in demanding environments like pharmaceutical or textile plants.
The compressor is equipped with a built-in high-precision water filtration and reverse osmosis system (optional based on model). This ensures that the lubricating water remains within the required purity levels, protecting the air end from scaling or mineral buildup.
